Brake application device comprising an electrically actuated wear-adjusting emergency release and auxiliary release device

ABSTRACT

A brake application device for vehicles, especially for rail vehicles, comprising a wear-adjusting device which is embodied in a brake actuator and comprises a helical gear which is provided with a threaded spindle and a nut as screw connection parts, said nut being screwed onto said threaded spindle. One of the screw connection parts of the helical gear is electrically driven in order to adjust the wear of the brakes and the other screw connection part of the helical gear for the emergency release and/or auxiliary release of the brakes.

PRIOR ART

The invention is based on a brake application system for vehicles,particularly for rail vehicles, containing a wear adjuster constructedas a tie rod or plunger rod adjuster and having a helical gear which isprovided with a threaded spindle and a nut to be screwed to the latter,as the screw connection parts, according to the type of claim 1.

A brake application system of this type is known from European PatentDocument EP 0 699 846 A2, which describes a wear adjuster for railvehicle brakes in the form of tie rod and plunger rod adjusters which,in the case of a brake pad and brake disc wear, keep the brake pad playconstant. This takes place by a change of length of the helical gear, inthe case of plunger rod adjusters, an increasing adjuster length causinga reduction of the brake pad play. The drive of the known helical gearoperates mechanically by way of a brake linkage with a plunger rodwhich, in the event of an excess stroke of a brake actuator constructedas a pneumatic cylinder—piston driving gear, is operated by a rockerlever. An emergency release of the brake acted upon by braking powertakes place by way of the pneumatic brake actuator; for the auxiliaryrelease in the case of a brake pad exchange, the threaded spindle isrotated manually.

The present invention is based on the object of further developing abrake application system of the initially mentioned type such that itrequires less space and its operation is easier and simpler.Furthermore, a more precise adjusting of the brake pad play should beachievable.

According to the invention, this object is achieved in that one screwconnection part of the helical gear is electrically driven for the wearadjustment and the other screw connection part of the helical screw iselectrically driven for the emergency and/or auxiliary release of thebrake.

ADVANTAGES OF THE INVENTION

As a result of the electric drive of the one screw connection part ofthe helical gear for the wear adjustment, the known brake linkage can beeliminated. Since the electric drive unit has a smaller size than thebrake linkage, space and weight are saved. The electric control linescan be integrated in a simple manner in different vehicle models and canbe laid in a space-saving manner. Furthermore, as a result of theelectric operation in comparison to a mechanical operation, a moreprecise adjusting of the brake pad play can be achieved.

In addition, according to the invention, both functions—the wearadjusting, on the one hand, and the emergency and/or auxiliary release,on the other hand—are implemented by means of one and the same helicalgear so that, by a combination of functions in one assembly, additionalspace and weight can be saved. The auxiliary release, which so far hadto be carried out separately in a manual manner for each and on eachbrake application system, is replaced by an electrically remotelyoperated auxiliary release, for example, from an engineer's cab of therail vehicle. In particular, all brake application systems of the railvehicle can be released by a common and one-time control, whereby themaintenance time is reduced.

By means of the measures indicated in the subclaims, advantageousfurther developments and improvements of the invention indicated inclaim 1 can be achieved.

According to a preferred embodiment of the invention, for the electricactuating of the one screw connection part, an electric drive unit isprovided which consists of an electric motor with a gearing arranged onthe output side, the gearing output being rotationally coupled with anelectrically actuated screw connection part. The electric motorpreferably is a d.c. motor; the gearing contains a planetary gearaxially adjoining the electric motor as well as one or more gearwheelstages arranged behind this planetary gearing.

Particularly preferable measures provide a clutch by which the one screwconnection part, in the event of the presence of an axial forceoriginating from a braking, can be non-rotatably coupled with anon-rotatable part, for example, a housing and otherwise can beuncoupled therefrom. As a result, the screw connection part loaded byway of the caliper levers of the brake application system by the brakingpower is supported on the housing and not on the electric drive unit,which can therefore be dimensioned to be smaller, was also contributesto a reduction of the size.

According to a further development, a sliding clutch is arranged betweenthe electric drive unit and the one screw connection part, which slidingclutch is constructed to be sliding through when stop positions arereached and is otherwise coupling. One stop position is formed, forexample, by the application of the brake pads on the brake disc, andanother stop position is formed by a screw connection end position inwhich the one screw connection part is screwed to the stop into theother screw connection part or vice-versa. In the latter case, the onescrew connection part would be rotated along with the other screwconnection part, and the rotating movement would be undesirablytransmitted to the electric drive unit. The sliding clutch thereforeprotects the electric drive unit from impacts when the stop positionsare reached in that it slides through in order to permit the motor tosoftly and gradually conclude its rotating movement and uncouples itfrom torques introduced by way of other components. The sliding clutchis preferably connected between the coupling and the electric driveunit.

In a particularly preferable manner, the electric drive unit of the onescrew connection part can be actuated independently of an electric driveunit of the other screw connection part. As a result, the functionscombined in one assembly—the wear adjustment, on the one hand, and theemergency and/or auxiliary release, on the other hand—, can be carriedout individually and independently of one another.

DRAWINGS

An embodiment of the invention is illustrated in the drawing and will beexplained in detail in the following description.

FIG. 1 is a longitudinal sectional view of a plunger rod adjuster of abrake application system of a rail vehicle according to a preferredembodiment in a position moved out to the maximal length;

FIG. 2 is a view of the plunger rod adjuster of FIG. 1 in a positionmoved in to the minimal length.

DESCRIPTION OF THE EMBODIMENT

For reasons of scale, FIG. 1 shows only a wear adjuster 1 in the form ofa plunger rod adjuster as part of an electromechanically, pneumaticallyor hydraulically operable brake application system which, according to apreferred embodiment, is intended for an urban railway or a subway,which plunger rod adjuster, in the position illustrated in FIG. 1, is ina position moved out to the maximal length, which corresponds to a highwear condition of the brake pads.

The plunger rod adjuster 1 contains a helical gear 2 which, as the screwconnection parts, has a threaded spindle 4 and a nut 8 which can bescrewed onto this threaded spindle 4 by means of a trapezoidal thread 6and is constructed as a tube-type part. The trapezoidal thread 6preferably is not self-locking. For the wear adjustment, the plunger rodadjuster 1 is designed to be operated electrically, for which anelectric drive unit 10 is provided which consists of an electric motor12 with a gearing 14 connected behind it, whose gearing output ispreferably rotationally coupled with the threaded spindle 4. As analternative, the nut 8 or the threaded spindle 4 and the nut 8 can alsobe designed to be electrically operated for adjusting the wear.

The electric motor is formed, for example, by a d.c. motor 12, and thegearing 14 is formed by a planetary gearing 16 axially adjoining thed.c. motor 12 as well as by a gearwheel stage 18 connected to the outputside of the planetary gearing 16. The d.c. motor 12, the planetarygearing 16 and the gear wheel stage 18 are arranged parallel and at aradial distance from the center axis 20 of the helical gear 2 and arehoused in a drive housing 22 flanged to a housing part 24, on the leftin FIG. 1, of the plunger rod adjuster 1, to which plunger rod adjuster1 a left caliper lever of a caliper of the brake application system islinked, which caliper lever is not shown. A housing part 26 which,viewed in the axial direction of the helical gear 2, is on the right issituated opposite the left housing part 24 and the right caliper leverof the caliper is linked to this right housing part 26. Such a caliperis sufficiently known and is described, for example, in European PatentDocument EP 0 699 846 A2, to whose entire disclosure content referenceis made here. The left housing part 24 and the right housing part 26 ofthe plunger rod adjuster 1 are held on one another at a spacing variableby means of the helical gear 2 in that, by extending the helical gear 2or the plunger rod adjuster 1, a wear adjustment can take place and thepad play between the brake pads and the brake disc, which enlarges withtime, can be reduced again and can be held at a constant value.

The gearing-output-side gearwheel 28 of the gearwheel stage 18 mesheswith a screw-side gearwheel 30 which, by means of a deep-groove ballbearing 32, is coaxially rotatably disposed on a cylindrical projection34 of a conical sleeve 36. By means of a sliding clutch 38 arranged onthe side of the screw-side gearwheel 30 pointing to the right housingpart 26, the electric drive unit 10 is coupled with the conical sleeve36. The sliding clutch 38 contains balls 40, which are pretensioned by adefined spring pressure in grooves constructed on the face of thescrew-side gearwheel 30 and which are guided in bores 42 of a ring 44non-rotatably held on the cylindrical projection 34 of the conicalsleeve 36. At torques greater than a defined slipping moment, the formclosure generated by the balls 40 pressed into the grooves is overcomeand the clutch 38 slides through, whereby the electric drive unit 10 isuncoupled from the threaded spindle 4. By the appropriate selection ofthe spring parameters and of the ball—groove geometry, the slippingmoment can be adapted to the momentarily existing requirements. In thepresent case, the clutch 38 slides through when the brake applicationsystem reaches stop positions, such as the position in which the brakepads come to rest on the brake disc or the position in which the plungerrod adjuster 1 is shortened to the minimal length (FIG. 2) and thethreaded spindle 4 is completely screwed into the nut 8.

The driving torque transmitted by means of the sliding clutch 38 to thering 44 is introduced into the conical sleeve 36, on whose bottom apin-shaped projection 46 is present whose radially outer surface forms abearing surface of a slide bearing 48, which bearing surface is slidablyand rotatably disposed in a housing-side bearing surface assigned to it.The slide bearing 48 is used as a bearing point of the threaded spindle4, which bearing point is on the left side in FIG. 1. The threadedspindle 4, in turn, is screwed by means of an end-side threaded pin 50into an internal thread existing in the projection 46 of the conicalsleeve 36 and is held there in a non-rotatable manner. As a result, theconical sleeve 36 can transmit the driving torque introduced by way ofthe sliding clutch 38 to the threaded spindle 4.

A cone clutch 52 containing at least two conical surfaces 56, 58, whichcan be stopped by mutual friction against one another and are arrangedin an oblique manner viewed in the axial direction, is arranged in frontof the electric drive unit 10, one of the conical surfaces 56 beingconstructed on the left housing part 24 and the other conical surface 58being constructed on the conical sleeve 36 screwed to the threadedspindle 4. When the threaded spindle 4 is axially loaded, the twoconical surfaces 56, 58 are pressed against one another in the directionof the conical narrowing, whereby the respectively taken-up rotatingposition of the threaded spindle 4 is fixed by frictional engagement oradherence and the axial load is supported by the left housing part 24.In particular, a transmission of the axial load as a torque to theelectric drive unit 10 is prevented. If, in contrast, no axial load ispresent, the cone clutch 52 is in the released state and the conicalsleeve 36, together with the threaded spindle 4, can rotate freely withrespect to the left housing part 24.

The tube-type nut 8 projects into a stepped passage opening 60 of theright housing part 26 and is rotatably disposed there by means of adeep-groove ball bearing 62 but is axially displaceably disposed withrespect to its inner race. A sleeve 66 is non-rotatably and axiallyfixedly held in the end of the nut 8 which points away from the lefthousing part 24 and, by means of its outer circumference, restsslidingly on a seal 64 received in the passage opening 60 of the righthousing part 26, the end of the sleeve 66 projecting out of the passageopening 60 being equipped with an application surface 68 for a screwingtool. In addition, by means of a sliding clutch 70, the nut 8 is coupledwith a coaxial free-wheel sleeve 71 of a lockable free wheel 74 which,on the one hand, is axially displaceably held on the nut 8 and, on theother hand, is supported by way of a thrust bearing 76 preferablyconstructed as an axial needle bearing against a radial wall 78 of theright housing part 26. The nut 8 is therefore disposed in a thrustbearing.

The sliding clutch 70 is preferably formed by two contrate gearings 80,82 meshing with one another by spring pressure in the axial direction.One contrate gearing 80 is constructed on a radially outer ring collarof the end of the nut 8 projecting into the right housing part 26, andthe other contrate gearing 82 is constructed on the radially innercircumferential surface of the free-wheel sleeve 72.

By means of a coil spring 86 supported at one end on the deep-grooveball bearing 62 and at the other end on an outer step 84 of the nut 8,the nut 8 is pretensioned against the free-wheel sleeve 72, so that thetwo contrate gearings 80, 82 are in a mutual engagement. When a slippingmoment is exceeded, the two contrate gearings 80, 82 are disengagedwhile the nut 6 is axially displaced in the direction of the lefthousing part 24, whereby the nut 8 can rotate with respect to thefree-wheel sleeve 72. The slipping moment of the sliding clutch 70 canbe adapted by the suitable selection of the spring parameters and of thecontrate gearings 80, 82.

In the right housing part 26, an electric drive unit 112 is accommodatedfor the emergency release and the auxiliary release of the brakeapplication system, “emergency release” being a braking power reductionof the brake application system acted upon by braking power, forexample, in the event of a failure of the brake actuator, and “auxiliaryrelease” being a release of the brake not acted upon by braking powerfor maintenance work, for example, for changing the brake pads.

The electric drive unit 112 consists of an electric motor preferablyconstructed as a d.c. motor 114, of a planetary gearing 116 as well asof a gearwheel stage 118, so that the two electric drive units 10, 112preferably have an identical construction. The gearing-output-sidegearwheel 120 of the gearwheel stage 118 meshes with a toothed sleeve 96which is coaxial with the helical gear 2 and which is rotatablyaccommodated in the right housing part 26 and is radially spaced by anannulus 102 with respect to a housing surface 100 which is flush withthe radially outer circumferential surface 98 of the free-wheel sleeve72 and axially adjoins the circumferential surface 98 of the free-wheelsleeve 72. A wrap spring 104 which is coaxial with respect to the centeraxis 20 of the helical gear 2 and has two pin-type ends 106, 108 bentaway oppositely in the radial direction is accommodated in the annulus102, one end 106 being formlockingly held in a radial passage bore ofthe toothed sleeve 96, and the other end 108 being formlockingly held ina radial passage bore of the free-wheel sleeve 72.

The toothed sleeve 96, the wrap spring 104, the free-wheel sleeve 72 andthe housing surface 100 together form a lockable free wheel as a wrapspring free wheel 74, which couples the electric drive unit 112 with thenut 8. More precisely, the wrap spring free wheel 74 is, on the onehand, constructed for rotating the nut 8 by means of the electric driveunit 112 in a direction against the wear adjustment and, on the otherhand, for locking this rotation when the rotation of the nut 8 is notcaused by the electric drive unit 112. The above-described slidingclutch 70 is arranged between the nut 8 and the wrap spring free wheel74.

Relative to an imagined point of intersection of the center axis 20 ofthe helical gear 2 and an imagined vertical center line of the plungerrod adjuster 1, the two electric drive units 10, 112 are arrangedessentially point-symmetrically with respect to one another, in whichcase they point toward one another starting from the end of the threadedspindle 4 or of the nut 8. More precisely, the drive unit 10 for thewear adjustment projects essentially from the drive-side end of thethreaded spindle 4 in the direction of the drive unit 112 for theemergency and auxiliary release, and the latter projects essentiallyfrom the drive-side end of the nut 8 in the direction of the drive unit10 for the wear adjustment. Both drive units 10, 112 actuate a singlehelical gear 2 for the combined wear adjustment and emergency orauxiliary release.

The right and the left housing part 24, 26 each consists of housingsections 122, 124 which are essentially symmetrical relative to thecenter axis 20 of the helical gear 2. The drive unit 10, 112 is in eachcase accommodated in one housing section 122, and one final positionsensor 126 respectively is accommodated in the housing section 124arranged on the other side of the center axis 20, which final positionsensor 126 is situated opposite a face-side surface 128 of the drivehousing 22 of the respectively other electric drive unit 10, 112. Thefinal position sensors are preferably constructed in the form ofmechanical final position switches 126, which are each actuated by theapplication of the face-side surface 128 of the drive housing 22 of theopposite drive unit 10, 112 and supply a signal for reaching theposition illustrated in FIG. 2, in which the plunger rod adjuster 1 hasmoved in to the minimal length, to a control device, which is not shownfor reasons of scale, whereupon the respectively actuated drive unit 10,112 is de-energized. At their ends pointing away from one another, thetwo housing sections 122, 124 of each housing part 24, 26 are in eachcase provided with one receiving device 132 for bolts, by which onecaliper lever respectively of the caliper is linked to each housing part24, 26.

Furthermore, a wrap spring 138 of another wrap spring free wheel 140 isarranged on a cylindrical projection 134 of the planetary-gearing-sidegearwheel 136 of the gearwheel stage 18 assigned to the drive unit 10for the wear adjustment. This wrap spring free wheel 140 blocks arotation of the gearwheel 136 in the direction against the wearadjustment and permits it to run freely in the opposite rotatingdirection.

As a result of the described construction of the plunger rod adjuster 1,by means of a single helical gear 2, of which one screw connection partrespectively is coupled with a separate drive unit, which is independentof the other drive unit, specifically, on the one hand, the threadedspindle 4 with one electric drive unit 10 and, on the other hand, thenut 8 with the other electric drive unit 112, the brake pad wear can becorrected and the brake can be released for emergencies and/or in anauxiliary manner.

Based on this background, the method of operation of the plunger rodadjuster 1 is as follows:

The wear adjustment, that is, the reduction of the brake pad play, whichexists between the brake pads and the brake disc and which has becometoo large as a result of wear, takes place in the brake-power-free brakerelease position. For this purpose, the d.c. motor 12 of the electricdrive unit 10 provided for the wear adjustment is controlled for apredetermined time and causes the threaded spindle 4 to rotate in onerotating direction by way of the sliding clutch 38 closed in the case ofa driving torque which is smaller than the slipping moment, during whichrotating movement the threaded spindle 4 is screwed out of the nut 8 andthe plunger rod adjuster 1 is thereby lengthened, which results in areduction of the brake pad play. FIG. 2 shows the plunger rod adjuster 1in a position in which it is moved out to its maximal length. Since thehelical gear 2 is thereby loaded by only very low axial forces, the coneclutch 52 is in the released position, so that the threaded spindle canrotate freely. The nut-side wrap spring free wheel 74 blocks arotating-along of the nut 8, which is not secured against a rotation perse, because a rotation of the nut 8 is transmitted by way of the slidingclutch 70 to the free-wheel sleeve 72 and from there to the wrap spring104 which then pulls tight and establishes a frictionally engagedconnection between the free-wheel sleeve 72 and the housing surface 100,whereby the nut 8 is non-rotatably supported on the right housing part26.

During a braking, the bearing pressure force resulting from the brakingpower existing at the brake pads and transmitted by way of the hingedcaliper levers of the caliper to the plunger rod adjuster 1 and actingthere in the axial direction could not be supported on the helical gear2 because the trapezoidal thread 6 between the threaded spindle 4 andthe nut 8 does not have a self-locking construction. As a result, theplunger rod adjuster 1 would be shortened under the influence of theaxial pressure force and thus an undesirable loss of braking power wouldbe caused. However, the cone clutch 52 closes under the effect of theaxial load by the pressing-together of the mutually assigned conicalsurfaces 56, 58 in a frictionally engaged manner and establishes anon-rotatable connection between the threaded spindle 4 and the lefthousing part 24. On the other hand, the nut-side sliding clutch 70constructed as a contrate gearing 80, 82 remains closed under axial loadand transmits the moment of reaction to the wrap spring 104 which thenpulls tight and supports the moment of reaction at the right housingpart 26. As a result, no shortening of the plunger rod adjuster 1 andthus no unintended loss of braking power can occur during a brakingoperation.

If a fault occurs, in the case of a brake actuator, which generates thebraking power of the brake application system, or in its control, whichhas the result that the brake actuator can no longer release the brakeacted upon by the braking power, this brake has to be subjected to anemergency release. For the emergency release of the brake, the electricdrive unit 112 is preferably controlled for the emergency and/orauxiliary release from the engineer's cab of the urban railroad orsubway, specifically in a rotating direction in which the wrap spring104 is expanded and, as a result, the previously existing frictionalengagement between the free-wheel sleeve 72 and the housing surface 100is eliminated, whereby the nut 8 has a free run in this rotatingdirection. The wrap spring 104 can therefore transmit the rotatingmovement introduced into it by way of the toothed sleeve 96 to thefree-wheel sleeve 72, by which the rotation is transmitted to the nowfreely running nut 8 by way of the sliding clutch 70 which is closedbecause it is not overloaded. As a result, the plunger rod adjuster 1 isshortened and the braking power is reduced. The plunger rod adjuster 1can thereby be shortened to the minimal length illustrated in FIG. 2 inwhich the nut 8 on the face side comes in contact with the bottom of theconical sleeve 36 and the final position switches 126 are actuated.

If, for maintenance work, the brake is to be moved into a position inwhich the brake pads are at a maximal distance from the brake disc, forexample, for exchanging the brake pads, the release of the brake canalso take place by way of the electric drive unit 112 for the emergencyand/or auxiliary release in the manner described above (auxiliaryrelease). Since, however, the torque is limited which can be transmittedby means of the nut-side wrap spring 104 expanded by the driving torqueand subjected to a bending stress, in the cases in which the helicalgear 2 is stiff, for example, because of icing, the nut 8 is rotateddirectly for shortening the plunger rod adjuster 1. This takes place inthe braking-power-free state by applying a screwing tool to theapplication surface 68 of the sleeve 66 non-rotatably connected with thenut 8, in which case the latter is manually rotated in a direction inwhich the plunger rod adjuster 1 is shortened to the minimal lengthillustrated in FIG. 2. The torque must be so large that the slidingclutch 70 arranged between the free-wheel sleeve 72 and the nut 8 canslip, while the wrap spring 104 of the wrap spring free wheel 74 blocksthe free-wheel sleeve 72 in this direction. In this case, the nut 8 isdisplaced so far away from the free-wheel sleeve 72 in the axialdirection that the two contrate gearings 80, 82 are disengaged.

The invention is not limited to plunger rod adjusters 1 of brakeapplication systems but can also be used for tie rod adjusters.

List of Reference Numbers

-   1 Plunger rod adjuster-   2 helical gear-   4 threaded spindle-   6 trapezoidal thread-   8 nut-   10 electric drive unit-   12 electric motor-   14 gearing-   16 planetary gearing-   18 gearwheel stage-   20 center axis-   22 drive housing-   24 left housing part-   26 right housing part-   28 gearwheel-   30 gearwheel-   32 deep-groove ball bearing-   34 cylindrical projection-   36 conical sleeve-   38 sliding clutch-   40 balls-   42 bores-   44 ring-   46 projection-   48 slide bearing-   50 threaded pin-   52 cone clutch-   56 conical surface-   58 conical surface-   60 passage opening-   62 deep-groove ball bearing-   64 seal-   66 sleeve-   68 application surface-   70 sliding clutch-   72 free-wheel sleeve-   74 free wheel-   76 axial bearing-   78 wall-   80 contrate gearing-   82 contrate gearing-   84 outer step-   86 coil spring-   96 toothed sleeve-   98 circumferential surface-   100 housing surface-   102 annulus-   104 wrap spring-   106 end-   108 end-   112 electric drive unit-   114 d.c. motor-   116 planetary gearing-   118 gearwheel stage-   120 gearwheel-   122 housing section-   124 housing section-   126 final position switch-   128 surface-   132 receiving device-   134 projection-   136 gearwheel-   138 wrap spring-   140 wrap spring free wheel

1. (canceled)
 2. The brake application system according to claim 20,wherein, for the electric driving of the one screw connection part anelectric drive unit is provided which consists of an electric motor witha gearing arranged on an output side, the gearing output of the gearingis rotationally coupled with the one screw connection part.
 3. The brakeapplication system according to claim 2, wherein the electric motorcomprises a d.c. motor, and the gearing comprises a planetary gearingaxially adjoining the d.c. motor as well as one or more gearwheel stagesarranged on its output side.
 4. The brake application system accordingto claim 2, including a clutch in front of the electric drive unit ofthe one screw connection part, by means of the clutch, in the event ofthe presence of an axial force originating from a braking, the one screwconnection part is non-rotatably coupled with a non-rotatable part andis otherwise uncoupled from the latter.
 5. The brake application systemaccording to claim 4, wherein the clutch includes a cone clutch havingat least two conical surfaces which can be stopped as a function offriction against one another and are arranged obliquely viewed in aneffective direction of the axial force.
 6. The brake application systemaccording to claim 5, wherein one of the conical surfaces is constructedon a housing and the other conical surface is constructed on a conicalsleeve non-rotatably connected with the one screw connection parts. 7.The brake application system according to claim 6, including a threadedpin of the one screw connection part is screwed into an internal threadconstructed in a bottom of the conical sleeve.
 8. The brake applicationsystem according to claim 7, including a gearwheel meshing with agearing-output-side gearwheel of a gearing and being coaxially rotatablydisposed on a cylindrical projection of the conical sleeve.
 9. The brakeapplication system according to claim 8, including a slip clutch isarranged between the electric drive unit and the one screw connectionpart; and the slip clutch is constructed to be slipping when stoppositions have been reached and is otherwise coupling.
 10. The brakeapplication system according to claim 9, wherein one stop position isformed by the application of the brake pads on the brake disc andanother stop position is formed by a screwing end position, in which theone screw connection part is screwed into the other screw connectionpart to the stop, or vice-versa.
 11. The brake application systemaccording to claim 10, wherein the slip clutch is arranged between thecone clutch and the electric drive unit of the one screw connectionpart.
 12. The brake application system according to claim 11, whereinthe slip clutch contains balls pretensioned by defined spring pressurein grooves, the grooves being constructed on a face of thegearing-output-side gearwheel, and the balls being held in bores of aring non-rotatably held on the cylindrical projection of the conicalsleeve.
 13. The brake application system according to claim 20, wherein,at least during the electric driving of the one screw connection part inone rotating direction for the wear adjustment, the other screwconnection part is held in a non-rotatable manner.
 14. The brakeapplication system according to claim 13, wherein the other screwconnection part is coupled with an electric drive unit for the emergencyand/or auxiliary release by unlockable free wheel; the unlockable freewheel permits a rotation of the other screw connection part by means ofthe electric drive unit in a direction against the wear adjustment and,is constructed for blocking this rotation if it is not caused by theelectric drive unit.
 15. The brake application system according to claim14, wherein another electric drive unit of the one screw connection partis actuated independently of the electric drive unit of the other screwconnection part.
 16. The brake application system according to claim 14,wherein the electric drive unit of the other screw connection partcontains an electric motor.
 17. The brake application system accordingto claim 14, wherein the other screw connection part is coupled by aslip clutch with the electric drive unit and has an application surfacefor the application of a rotating tool.
 18. The brake application systemaccording to claim 20, characterized in that the one screw connectionpart is formed by the threaded spindle and the other screw connectionpart is formed by the nut.
 19. The brake application system according toclaim 18, including the unlockable free wheel formed as a coil springfree wheel between a cylindrical wall of a non-rotatable part and asleeve rotating along with the nut.
 20. A brake application system forvehicles, particularly for rail vehicles, comprising: a wear adjusterhaving a helical gear which has a threaded spindle and a nut which canbe screwed thereto as screw connection parts; one screw connection partof the helical gear being electrically driven for the wear adjusting;and another screw connection part of the helical gear being electricallydriven for an emergency and/or auxiliary release of the brake.